This is the result of a compilation of factors.
Yes, lawyers do try to keep an aura of confusion around most things. It is was simple, the people wouldn't pay us...then hunt us for sport.
(Use $20's a bait, then go for a double lung shot as the lawyer bends to pick up the $$. Go for the older ones because the meat is pre-marinated with good whiskey...)
Law related to lethal force isn't all that complex. The application of it as the situation is occuring can be, and what is really needed in my opinion is a classroom & force on force scenario training block of instruction on the application of the law to help people sort out the bullshit from the real-shit.
Further, people are very gear-centric when they should be software-centric.
It's easier to buy gear than it is to understand how & when to use it. We know from the text of the law what size the gun can be, how many rounds it holds...but the intangables surrounding it aren't as well documented in an easily searchable format.
That's partly because the legal reporting is very fucked up. Only cases which are tried make it into case reporters, and then usually only appealed cases. Plead out cases aren't reported, nor are settled cases (which are usually confidential).
Further, they are only aplicable within that state, so people are SOL if something on point didn't go down in your state, then it's just advisory, not binding.
Even if you wanted to search for it, you can't just google it because the companies who run the search engines charge, so you'd have to hit a library which has westlaw or lexis-nexis to even start.
This, and other factors, result in people getting a somewhat skewed view, to one degree or another, based on partial information which they may or may not know is partial, which also may or may not be on point to that person's situation.
Also, people may know something was important in a case - but not why it was important.
Take Harold Fish and the infamous 10mm.
The 10mm was a talking point. It didn't make the case be prosecuted...the 4 hour confusing, rambling, self contradicting statement, and the statement of people who's timeline contradicted his did that.
The 10mm was used in the trial argument, but that's because it offered a nice hook for a closing argument.
As to the AR v. Shotgun debate for the home...to me, it's a false argument. One is an assault rifle, the other is the next best thing to a machine gun.
If you have screwed the pooch to the degree your weapon is being discussed, you are way beyond the point the other would have helped you.
Actions matter.
Post incident statements matter.
What the gun look like, what it was loaded with...that's important, but not to the degree it's made out to be, nor for the reasons people believe.
As to things brought out in a way lay-people would think about it, that's very true; however, more than one thing has to go wrong before you start doing that.
Once you are in the clusterfuck...olive oil & vegtables are used differently, shall we say...than the common usage. But you have to get to the clusterfuck first.
Same thing with your dreaded Glock with the sniper sights (warren tacticals) loaded with bullets outlawed by our military (WWB 115 JHP).
I hope I'm making things a bit less confusing, and that I'm not trying to talk down to anyone, because it's not my intention to do that.
The view is a bit different from the other side of the fun-house mirror, and I'm just trying to convey that to get across that people have a LOT more lee-way in weapons and use of force than they might sometimes believe.